In particular, the invention relates to a spray nozzle for a fluid product comprising:
a front wall,
an outlet channel extending through said front wall, said outlet channel being delimited by a lateral surface substantially of revolution about an axis perpendicular to the front wall, the lateral surface of the outlet channel comprising at least one relief arranged radially in relation to the axis,
an intake conduit suitable for feeding the fluid product into the outlet channel, the intake conduit and the outlet channel being suitable for entraining the fluid product in a rotation movement about the axis in a direction of rotation, said intake conduit extending in a plane perpendicular to the axis, substantially tangentially in relation to the lateral surface of the outlet channel, between an upstream end suitable for being fed with the fluid product and a downstream end opening into the lateral surface of the outlet channel.
Such a spray nozzle is used to obtain, at the exit from the outlet channel, a dispensing to the outside of the fluid product under pressure in the form of an aerosol composed of individual droplets, and having a conical shape with a determined spraying angle.
Such a spray nozzle is known in particular from document EP-0 796 661 which provides for projections formed on the lateral surface of a swirl chamber.
However, the known spray nozzle poses problems for spraying a viscous fluid product, i.e. a fluid product having a viscosity greater than 0.001 Pa·s at 20° C.
Actually, the lateral surface of the outlet channel causes an uncontrolled disturbance of the circulation of the fluid product in the outlet channel. The result is a global loss of head for the fluid product, and a reduction in the pressure at which the fluid product is entrained.
The fluid product leaves the spray nozzle in the form of an aerosol comprising droplets of various dimensions, possibly substantial, and the spraying angle of which is reduced, for example to 10°, namely in the form of a jet.